Dr Hussain Patel
MBCHB, MD, FRANZCO
Based in Auckland, Hussain is an Ophthalmologist with expertise in the field of glaucoma and cataract surgery
Author: B Gibson Glaucoma New Zealand based on Dr Hussain Patel’s presentation at the Glaucoma NZ Professional Symposium in Auckland, on 16th May 2021.
Primary Open Angle Glaucoma (POAG) is the most common form of glaucoma, with nearly 80 million people affected around the world. The number of people affected varies widely depending on where you are located and your ethnicity. There are higher rates of POAG in Africa and Latin America and much lower rates in the Middle East. In Asia, a particular type of glaucoma, called Angle Closure Glaucoma (ACG), is much more common than anywhere else in the world. The prevalence of glaucoma also increases dramatically in populations aged over 65.
Taking a closer look at New Zealand, we find that the prevalence of glaucoma varies widely depending on ethnicity. Of particular interest is that there appear to be very low rates of glaucoma in Maori and Pacific peoples. Despite Maori making up 8% and Pacific peoples 9% of the ADHB population, a study involving glaucoma patients from Auckland District Health Board (ADHB) found that Maori only made up 0.5% of all people affected by POAG and Pacific peoples only 0.9%. This means that POAG was 16 times less for Maori and 10 times less for Pacific peoples than what would be expected. Although POAG was very rare, other types of glaucoma are more common in Maori and Pacific peoples, including ACG and glaucoma secondary to other conditions like diabetes. In contrast, those of Caucasian and Indian ethnicity made up a greater proportion of glaucoma patients than expected in this study. Interestingly, the average age that Maori (60 years) and Pacific peoples (57 years) were affected was also much younger than those of Caucasian ethnicity (69 years).
The explanation for the low rates of glaucoma in Maori and Pacific peoples may be related to three factors. The first is population age structure, with Maori and Pacific peoples having a lower life expectancy than Caucasians. According to statistics New Zealand, 17.1% of the Caucasian population are over 65 years while only 5.4% and 4.7% of the Maori and Pacific population, respectively, are over 65. Since glaucoma typically a disease of the elderly, the underrepresentation of Maori and Pacific peoples in glaucoma may be due to the lower life expectancy of the Maori and Pacific peoples. The second factor may be related to access to healthcare, with studies showing Maori and Pacific peoples have generally poorer access to and usage of primary healthcare services, including optometrists, where glaucoma is often diagnosed. A third factor could be the presence of genes or genetic factors within Maori and Pacific peoples that protect them from glaucoma. Interestingly, studies have demonstrated that Maori and Pacific peoples share a common Mongolian ancestry and may have the same ‘genetic protection’ against glaucoma.
It is more important than ever that New Zealanders with glaucoma stand up and be counted. In November, Glaucoma NZ (GNZ) will be launching the New Zealand Glaucoma Register. It will be hosted within the redesigned GNZ website and will target all primary diagnoses of glaucoma in New Zealand. The registry will approach the disease in a data-driven way to determine the incidence of glaucoma in New Zealand and evaluate subsequent procedural interventions to advance treatments and accelerate future research.
This population-based registry will primarily collect and store glaucoma incidence data. We will seek to understand the occurrence of glaucoma in a defined population in specified time periods to develop projections of the glaucoma burden in New Zealand demographics. This data will be important in guiding the design of glaucoma screening, treatment, and related public health strategies for the future.